Seasonal Succession in the High Arctic

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Our long-term objective is to create a predictive model of seasonal succession in microbial communities in the High Arctic. Our specific goals are to test several hypotheses about the mechanisms of the successional change. For this, we have developed a synergistic experimental approach that combines the use of state-of-the-art “meta-omics” and advanced cultivation tools.

We collected soil samples at the beginning and end of the high arctic summer from varying geographical locations in proximity to Thule Air Base in Thule, Greenland. Samples were collected from various site types ranging from poor soil with no vegetation to rich soil with ample vegetation and water. We also collected samples from different lakes with a similar range of observed vegetation. These samples were then processed for 16S, metagenomics, and metatranscriptomics sequencing.

Our 16S data showed a high abundance of unclassified Proteobacteria and Bacteroidetes in nearly all of the samples. This data was used to select the site that contained the most overlap in microbial diversity between the different sites. Environmental cultivation chambers were then deployed to that site allowing us to isolate bacteria in situ. This approach allowed us to isolate several hundred novel bacterial isolates, 41 of which have had their genomes sequenced to date. Additionally, we have also generated metagenomics data and metatranscriptomics data from a subset of the samples collected. The dataset collected from these “meta-omics” approaches will be used to characterize population dynamics and mechanistic changes in the microbial community during the transition between seasons in the high arctic.